Sheet packages, allowing the loading of a whole package storing and protecting a stack of sheets into a printer for refilling the printer with sheets, are well known. An example of such a sheet package has been disclosed in Japanese Patent Provisional Publication No.SHO60-97145, for example. According to the Publication, a stack of sheets is preserved in a box-shaped package made of a material like cardboard. The package is provided with a perforated line so that a part of the package making contact with a sheet feed roller can be removed. When the package is loaded in a printer, the user removes the unnecessary part from the package along the perforated line and sets the package directly in the printer.
Some users of sheet packages hope to form an identification part at a prescribed position on such a package member, read information from the identification part with a sensor of the printer when the sheet package is loaded in the printer, and utilize the information for processes executed by the printer. An example of a sheet package having such a configuration has been disclosed in Japanese Patent Provisional Publication No. SHO60-97145. According to the Publication, information on the type of sheets stored in the package member, etc. is indicated by the identification part and the information is read out from the identification part by the printer, by which the control of a print mechanism unit, for example, can be changed depending on the type of the sheets stored in the package member, etc.